ACID FAST STAIN: ZIEHL-NEELSEN

Technical Data #ZIEHLa / 2013.07.22

The Ziehl-Neelsen Stain is used to stain acid-fast organisms as well as Mycobacterium sp. in specimens and in culture. Ziehl-Neelsen Stain uses an hot procedure to wax content of Mycobacterium. Acid fast microorganisms are resistant to acid decolorizer, with a remaining reddish color stained and blue background.

FORMULAin grams per liter purified filtered water

Carbol Fuchsine, Stain

Basic Fuchsine

3,0

Phenol

50,0

Ethanol, Denatured

100,0 ml

Water, deionized

950,0 ml

Acid-Alcohol, Decolorizer

Ethanol, denatured

970,0 ml

Hydrochloric Acid, concentrated

30,0 ml

Methylene Blue, Counterstain

Methylene Blue

3,0

Water, deionized

1000,0 ml

PRECAUTIONSThis medium is for IN VITRO diagnostic use only.

STORAGEStore in tightly-sealed containers at 15-30ºC in the dark.

SIGN OF DETERIORATIONStains should not be used if they show signs of deterioration or if the expiration date has passed.

PROCEDURE

Prepare the smears as described in previous standardized methods directly from specimens or from an overnight growth.

Rinse thouroughly with tap water and decolorize with Acid-Alcohol until pink color flow disappears.

Rinse with tap water and add counterstain with Methylene Blue for 30 seconds.

Rinse with tap water. Blot dry and examine microscopically.

QUALITY CONTROL

Organisms

ATCC

Color

Morphology

Escherichia coli

25922

blue

bacilli

Mycobacterium tuberculosis

25177

reddish

large bacilli

LIMITATIONS OF METHODSlides of acid-fast should be stained individually to prevent acid fast bacilli carry-over from one slide to another. This is a part of identification. Other methods may be required.